$(a)$ What are the two ways by which an infectious disease can be treated?
$(b)$ Explain the mode of action of antibiotics.

(N/A) The two ways to treat an infectious disease are:
$(i)$ To reduce the effects of the disease: This involves symptomatic treatment,such as taking medicines to lower fever,reduce pain,or manage inflammation,while the body's immune system fights the infection.
$(ii)$ To kill the cause of the disease: This involves taking specific medicines like antibiotics,antivirals,or antifungals that target and eliminate the specific pathogen (bacteria,virus,or fungus) causing the infection.
$(b)$ Antibiotics work by blocking specific biochemical pathways that are essential for the survival of bacteria. For example,many antibiotics block the bacterial process of building a cell wall. Since human cells do not build cell walls in the same way,these drugs kill the bacteria without harming human cells.